The collectible virtual card game, which released in 2014, hit 10 million registrations within a month of its debut on PC, and expanded to iOS and Android devices later that same year.

"There are more guests in the Tavern than ever before, but there’s always room for more!" Blizzard said via a blog post (thanks, Gamasutra). "We’re humbled and grateful that so many players have chosen to join us in the Hearthstone Tavern! As our way of saying thank you, we’re throwing a party! Join us by logging into Hearthstone from November 7 through November 11, play with friends, and be gifted with tokens of our appreciation!"

To celebrate the milestone, from tomorrow, 10am PST (6pm UK time) until November 11th, players who log in will receive six free The Boomsday Project card packs. Players can also bag 100 gold each time you play a friendly challenge, a quest repeatable up to five times during the celebratory period providing you've completed the introductory quests “First Blood” and “The Duelist” (or “Ready for Action” if you’re a returning player).

The Hearthstones and Elder Scrolls Legends of the gaming world are expected to drive digital collectible card game (CCG) earnings to $1.5 billion (£1.16 billion) in 2018 – and the numbers will rise to around $2 billion (£1.55 billion) by 2020. The figures come from a recent report which points out almost three quarters (71 per cent) of digital CCG players do so on their smartphones – so developers wanting a slice of those billions might want to look to a mobile-first approach.